Entries tagged with oppp

The tack welds for the bend, hinge, and closure are in. It's time for a test fit.

Hmmm.

Not too bad, not perfect. I started the half-inch-radius bend in the front just a smidge too far up the hatch so there's a 1/16" or so mismatch backward and up.

Also, I had a little trouble with one of the tack welds for the right hinge fitting. It's angled up slightly to put the pin at the right height, so it's not actually sitting flat against the 22ga steel the hatch is made of. The not-quite-a-lap-weld Just Would Not Bridge.

Cranking the amps up to somewhere between Righteous Fury and Raining Hellfire did the trick, but thank goodness for the aluminum chill strip or I'd have punched a dime size hole right through. As it is, it's nothing a grinder can't fix.

I think I'm going with this. It's not like the OEM enclosure is exactly precision manufacture either.

I didn't notice till after I'd finished that the bend depth adjustment had slipped, so the bends are a little rounder than I'd have liked, but meh. Let's tack weld it and see how well it fits before complaining too hard.

A nice, 22ga steel blank to make the new control panel for the laser cutter. No lasers involved, just a band saw and a scroll saw. Scotch tape protects the cut lines from rubbing and acts as a blade lubricant.

Given the two laser control panels and the design comparison,
what's the actual goal here?

The first goal is functional: I need to add a number of
new control and status functions.

Second: I am a vain man, and I want this tool to look a little
less hokey. Not entirely, just a little. I mean, I gotta be me.

The biggest addition will be a software control for the laser. I
somewhat arbitrarily decided to go with a rebranded Anywells
controller from LightObject-- I'll find out later if that was a
good idea or not.

The huge, spread-out, not-calibrated-to-anything digital PWM
laser current control gets replaced by a thumbwheel implementing
a Kelvin ladder. And instead of a 7-segment LED display that
simply goes from 0-100, I'll use a good-old analog meter that
measures actual milliampres.

While we're at it, a matching analog meter reads cooling water
temperature.

Like on the American control panel, the key switch is the only
power on-off, and the emergency stop will be a real
immediate-stop interlock.

I have an onboard air assist, so that needs a switch too, along
with a lighting switch and two switched laser pointers, one a
centering beam and another for focus.

And, why not steal the tube runtime meter from the nifty panel as
well? :-)

Last of all, arrange it in a more 'American' style: functions
grouped together, consistent labeling, and no angry color salad.
And just one or two inside jokes, because the tool is still a bit
hokey.

A few weeks ago, I accepted my first order for a T43 backlight kit. It turned out to be a c-c-c-c-c-combo-breaker!

In the early days of software-controlled brightness, ThinkPads used an analog brightness signal like just about every notebook. It was generated by one of the D-to-A pins on the embedded Renesas H8S microntroller all ThinkPads used.

As of the X40, ThinkPads went to using a digital PWM brightness control generated by the Intel Centrino ICH Southbridge. This made them kind of weird by laptop standards. It's one of the reasons I had to cons up custom LED drivers for my ThinkPad brightness kits.

In general, the T and X series of the same generation shared a basic architecture. The planars were quite different, but the chipset and basic design were the same. Not so with the T4X and X4X.

The X40-series is a completely different design from the T40-series. It uses a PWM brightness control. The T40, however, is analog like the older machines, which threw me for a loop at first. The good news is that I'd made working drivers for the X2x, X3x, T2x and T3x beforehand, so once I realized the T4x was an 'old' style, getting it to work wasn't hard. I can use the same positive-analog TLD2 hack that worked on the earlier models.

The bad news is all my fabrication, based on the TLD3, is geared toward the PWM-based ThinkPads. The TLD3 boards aren't able to use a positive-analog brightness signal no matter the hack. For a TLD3, it's PWM input or nothing.

I have on hand ~ 1500 TLD3 PCBs, waiting to be populated, for the usual PWM kits. I have only ~ 20 TLD2 PCBs left that can be pressed into analog use.

The control panel for my Chinese K40 laser cutter is very very Chinese. That's not a truism, condemnation, or praise. It is what it is.

To be fair, it works, and that's no backhanded compliment. But it has a number of functional and design sins my Western eye simply can't leave be.

First and foremost, it spreads precious little functionality over the entire available space. I need to add additional controls and an entire DSP panel, and there's simply no room to do so.

And that's not for the jam-packed functionality. Pretty much the entire 7x5 square in the middle is doing the job of a single knob or thumbwheel. But a single knob would not be 'cool', and so we have this monstrosity of an ampre control that's not even calibrated in amperes/milliampres (despite the legend).

It has three (three!) 'ON' switches wired in series. A rocker, a key switch, and a stop paddle. They all do the same thing.

The temperature gauge, at the top, is simply a little LCD-readout battery powered number. It works, and it's reasonably accurate. But it is hard to read. And it's smack in the middle of space that could be used more efficiently.

I will give this particular kudo: It uses sans-serif fonts, which gets a 'well done!' And there's no Comic Sans.

I won't even complain about the pastel lavender gradient, except I just did.

Another post I meant to make a while ago... George, my Tiniest of Tinies, has taken a liking to lasers and mirrors.

eBay and Amazon advertise a number of little Chinese 'optics experiments' kits with a laser line source that makes three parallel beams, a number of partially frosted lenses, prisms and mirrors, and a few other fun things. There's no English version but it looked like a good gift anyway.

Using Google's realtime image translate and no knowledge of technical Chinese whatsoever, I cobbled together a partly translated box and a translated instruction manual. Unless the original Chinese was quite subtle, I don't think there was actually a ton of useful content there, but hey.

Meters (and digital displays) are nice for detailed readings when you're standing right in front of them, but I still want to know what's going on from across the room, especially with a laser cutter using an experimental cooling system as likely to go horribly awry as work perfectly.

A nice, brightly lit meter that changes illumination color based on the potion of the scale it's in does the job nicely. Part readout, part indicator light, and it's no worse than a regular meter for the colorblind

....and, of course, immediately after mastering the water slide decal-fu, I discover the laser printer will, with no intermediate steps, print and fuse directly to the polyester diffuser sheet thankyouverymuch.

Ah well. Knowledge gained for next time. Hmmm.... I wonder upon what else this thing will print directly.

First try went surprisingly well, but not perfectly, so of
course I spent a day or two dialing everything in for future
reference. The directions on the package leave out a few helpful
tips.

Paper setting

Most importantly, the instructions stress over and over that a
laser printer can melt the decal medium*, and so recommend settings
that... did not work well in my particular printer.

I have a Color LaserJet MFP277dw, a popular choice for home
printers right now (and I'm pretty happy with it). This printer
has a low-temp fuser, and the recommended 'plain paper' setting
for decals wasn't fusing the toner to the decal sheet reliably. The print tracked
down the page (left side of the pic), and also tended to rub off
after printing. The slower, higher-temperature 'transparency'
setting works perfectly (right side of pic), and the print is
durable to rubbing and scraping. Win.

Soaking and sliding

Secondly the instructions recommend soaking in hot water (good
idea) for 20-30 seconds (in boiling hot water, maybe). I found
a minute to be more like it, it depends on the actual
temperature. Ideally, pull the decal out just before the edges
start lifting from the backing.

The decal itself appears to be a vinyl of some sort. When
it's hot, it's stretchy and pliable. When it cools back down, it
becomes fairly stiff. In the usual 'building models' case, you
probably want the label to conform to the target surface, so
slide and apply while hot (being careful not to stretch the decal
entirely out of shape).

For my use (meter scales) I want the decal to preserve its
dimensions exactly. Letting the decal cool to room temperature
before application works perfectly!

*The decal media is Papilio Laser Water-slide Decal Paper
from texascraft.com. I've been using various specialty Papilio
inkjet and laser media for more than ten years and have always
been happy with them. These days it needs to be said: I've not
been paid for any kind of endorsement, and have not been gifted
any free or discounted product. I'm just a happy customer.
There may be better stuff out there, but I've not bothered to
look for it--- and that's coming from a perfectionist who's
never satisfied with anything.

I needed a few chunks of acrylic that were a little thicker than anything in my supply closet. Cyanoacrylate (superglue) bonds PMMA nicely, makes an optically clear joint, is easier to work with than acrylic-specific solvent glues, and doesn't add nasty internal stresses to the plastic.

On the downside, the bond isn't quite as fast (I suppose this is just as easily an upside) and the index of refraction of the glue won't be quite the same as the sheet. A perfect joint will still be noticeable right around the critical angle where seam's angle of total internal reflection will be a little different from the rest of the plastic.

IMHBCO that's small price to pay for getting perfect, strong, bubble-free joints every time without getting light-headed indoors.

Pic related: two in-progress parts curing and my go-to favorite CA glue. Once the glue is fully cured, I'll mill and polish them into rough lenses.

I hate to do this to a nice indicator made in the US, but it's the year 2000+17 and still no one has digitized any of the classic industrial control typefaces used by American manufacturers in the early- and mid-20th century.

A few used Futura or a close knockoff, but that sticks out a little too much. And no, Sublime is not a valid answer either. I used Leroy pen sets. Sublime is neither authentic nor true to purpose, it's just a more subtle kitch font.

Some people collect old video games, others old equipment... I
used to leaf though control indicator catalogues like they were
porn rags, hence, this babby duck's lifelong fascination with
analog meters and LEDs. It's the industrial design I grew up
with. No color LCD screen can compare.

TD (@enginetankard) will concur--- I wouldn't shut up about it when he was here.

Chinese laser cutters often come with a little air pump; it's used to blow smoke away from the optics while cutting. You're supposed to set it up somewhere near the machine, and run an air tube in. It's a simple little AC coil/solenoid attached to a piston. It also vibrates enough that it will walk across a workbench under its own power unless you bolt it to something.
I want my air pump internal to the cutter, and I want it automatically controlled to only be on when cutting. Vibration would be a major problem mounting it inside the case, so I took two of the little ones, machined a custom output valve housing/gasket and connected them in opposing orientation. Viola! No vibration.

I've built up quite a pile of project pics I took meaning to post, then never got around to it.

OK, so, laser cutter.

China sells a lot of cheap cheap cheap "It's so cheap I can't believe that price covers shipping let alone materials" maker tools. Some are better than others, and many barely work for their intended purpose out of the box. Overall, plan to get what you pay for, and I mean that in both the good and bad senses.

Most of these tools make decent starting kits though! Research a bit, then choose the kit with the most parts you want to keep (or the fewest you plan to toss).

I bought a K40 variant (SL320) on AliExpress, and I'm building it into a complete cutter now. It has a decent X/Y stage, came with a good tube (which I promptly broke while being an idiot), a larger than normal case, tubing, flow sensor, air assist head, and a better than average power supply. It also came with an exhaust fan and aquarium pump I don't plan to use, a useless Z-stage, and an air pump that makes half of the ideal.

Others are already doing a good, detailed job of documenting their K40 builds. I've been referring to Dons Things and Tims Machines extensively for tips in my own build. So, I'm going to stick to pictures, terse captions, and the few things I've uncovered that I haven't seen solved elsewhere.

I don't want my water cooling tubing dangling out back to an open bucket and a failure-prone aquarium pump, and I'm pretty sure an external chiller is overkill. I want a fully internal, closed water cooling loop. Water cooling may be useless (if still cool) for PCs these days (ha ha, see what I did there), but it does mean nice cooling parts are cheap and plentiful for other uses.

So, step 1: shoehorn in the biggest possible radiator core. And by biggest possible, I mean, "move everything else as far out of the way as I can to make more room". That starts with lifting the laser tube tray up by about 2cm. The original mounting flange is just tack-welded on. It's easy to pop it right off.

The limitation to how much higher I can go is actually the clearance of the mirrors along the left side, and the XY stage fitting under the door opening lip in the front. You can see I also nibbled off about half the depth of the left side of the door opening lip.